Tofu: love it or hate it, you have to admit that it's a pretty interesting food - its inherent blandness making it the perfect canvas for lots of bold flavors. Made from just soy milk (itself just soybeans and water) and a coagulant (usually an acid, salt or enzyme), the result can be creamy, firm or anywhere in between. Tofu's culinary uses are just as varied, from savory to sweet. I happen to love tofu in just about every form.
A Brief History
As we mentioned in our post on soy milk, soybeans are thought to be native to China, where they have been cultivated for millennia. Recent data shows that there may have been several points of domestication in East Asia (including Northern China, Japan and Korea), some dating back as far as 5,500 years ago. According to researchers at Washington State University, the first written record of soybeans comes from China, around 200 BCE; the beans were apparently used medicinally.
Tofu originated in China, according to the Oxford Companion to Food, where it first appeared in Chinese literature in the 10th century CE. There is unsubstantiated speculation that tofu-making was an adaptation of Mongol cheese-making; and indeed, the methods of making fresh cheeses, like ricotta, and tofu are very similar.
- Nigari,a traditional Japanese curdling agent, is a mineral-rich byproduct of the salt-making process. Nigari is made by allowing saltwater to evaporate, which leaves behind sea salt (calcium chloride) and nigari. It can also be made by boiling seawater or through reverse osmosis.
- In Japanese cuisine, tofu is formed using a box traditionally made from Japanese cypress (hinoki), called a tsukuriki. You may not have access to Japanese cypress, but you can still make your own wooden tofu press.
- Flavor and texture varies slightly depending on the type of coagulant is used. In Chinese cuisine, calcium sulphate is common.
- According to Serious Eats, Benjamin Franklin was the first American to write about tofu in the late 18th century.
Cultivation and Production
Soybeans (Glycine max) are in the Fabaceae (legume) family, along with peas, beans, alfalfa and peanuts. Soybeans grown to make tofu are harvested when mature - this basically means that the beans are allowed to dry in their pods. Soybeans grow similarly to bush beans - they require warm soil and produce fairly bushy, upright plants that can grow as large as three to four feet tall. The US, Brazil, Argentina and China are the top worldwide producers, although most soy grown in these countries are used for animal feed (more on that, below).
According to the USDA, in 2014, 94 percent of all soy acreage planted in the US is genetically modified (GM) to be herbicide-tolerant (HT), up from only 17 percent in 1997. HT soybean plants, developed by the agricultural giant Monsanto, are resistant to herbicides that are used to control weeds - namely Roundup (glyphosate), an herbicide originally developed by...you guessed it: Monsanto. Unfortunately, the increased use of glyphosate has resulted in "superweeds" resistant to the herbicide, in some cases necessitating the use of different herbicides and mechanical tilling.
Soy, just following corn, is the second largest cash crop grown in the US, with over 84 million acres planted in 2014. What happens to all of this soy, you ask? A whole lot of soybeans are pressed into oil, much of which is hydrogenated or partially hydrogenated (read: loaded with heart unhealthy transfat) and used in processed foods and for frying. Much non-organic soybean oil is extracted using hexane, a chemical that has been linked to negative neurological effects. The remaining "soy meal" - what is left after pressing the beans for oil - is frequently used for industrial livestock feed in concentrated animal feeding operations (CAFOs).
Look for organic and/or locally made tofu if you're concerned about any of these issues, or make your own, from organic soy beans!
Tofu comes in a wide range of textures and flavors, depending on how it was processed, how long it was pressed and a number of other variables. Some of the most common include:
- Plain (or block) tofu: Snowy white or off-white, plain tofu is usually cut into large blocks and stored or packaged in water. Plain tofu is usually fairly firm in texture and can be used in a number of different ways, from stir-frying to soups to noodle dishes. You can often find plain tofu labeled by how firm it is (medium, firm, extra firm, etc.).
- Silken tofu: Silken or soft tofu is just that: soft and scoop-able, with a silky texture. It's used most often in desserts, smoothies and salad dressings, but it also shines in savory dishes, like the classic Szechuan mapo tofu.
- Frozen tofu: Freezing tofu changes its texture, making it spongier. This, of course, allows it to soak up sauces in a most delectable way. You can freeze tofu yourself; it's best to slice or cut into the sizes you desire first.
- Fermented and pickled tofu: Tofu can be fermented and pickled using soy sauce, miso, rice wine, vinegar and more. It ranges from mild to super stinky (like a good blue cheese!).
- Other tofu products: You can find tofu noodles, tofu balls, tofu pouches and more in many Asian markets.
Tofu in general is very high in protein and low in fat. The Oxford Companion to Food notes that turning soy beans into tofu makes the protein in the beans more bio-available. The types of minerals in tofu vary depending upon the type of coagulant used, but most commercial tofus are high in calcium, iron, magnesium and manganese. And as we mentioned in our post on soy milk, soy (in general) has gotten a bad rap in the press in recent years for containing supposed "feminizing" hormones like estrogen. Research, however, is still inconclusive about soy products' hormone-like effects on the body.
Video: Homemade Soymilk
What to Do with It and Cooking
Tofu is as versatile a food stuff as you can get, and in many cultures, tofu is a protein-loaded staple food with a deep culinary history. In Japan, China and Korea, tofu's culinary importance is reflected in the many forms of the food, and the many products it is made with - from deep-fried tofu, to tofu "puddings," to many varieties of fermented or pickled tofu. In its various forms, tofu can be stir-fried, deep fried, braised, boiled, pureed (into tofu puddings, custards and smoothies), steamed and baked. Crumbled tofu makes a great addition to veggie burgers and a nice substitute for scrambled eggs.
For many of these cooking methods, it helps to reduce the water content in the tofu by, at the very least, patting thoroughly with paper towels. To make even firmer tofu with even less water content, you can press your tofu by wrapping it in paper towels and weighing it down (put a plate on top of it, and something heavy, like a 28 ounce can of tomatoes) for 15-20 minutes.
Making your own tofu is fairly easy - you just need plain, unsweetened soy milk and whatever coagulant you have on hand, from lemon juice to vinegar to nigari. (See below for a recipe.)
Serious Eats has a great guide to cooking with tofu - with recipe suggestions - if you want a deeper dive.
Tofu can be stored in a covered container of water in the refrigerator for one to two weeks. Change the water daily to maintain freshness.
Recipe: Homemade Tofu
It's surprisingly easy to make your own tofu at home - all you need is soy milk, the coagulant of your choice and a little time. Get even more DIY and make your own soy milk first!
2 liters plain, unsweetened soy milk (from 3 cups of soybeans, if homemade)
Your choice of coagulant:
4 tablespoons freshly-squeezed lemon juice or 2 teaspoons nigari dissolved in one cup warm water or 2 teaspoons Epsom salts dissolved in one cup warm water or3 tablespoons vinegar
Special Equipment: thermometer, cheesecloth, container with holes (such as a tofu press or small colander)
- In a large pot, heat soy milk over medium heat, stirring occasionally, for 15-20 minutes until soy milk reaches 160-170°F on a thermometer.
- Turn off the heat. While gently stirring, add 3/4 of the coagulant of your choice. Let the mixture stand for 3-5 minutes. If you see milky liquid, add the remainder of the coagulant, gently stir, and let stand for an additional minute. You should see small white curds separating from amber-colored liquid.
- In a sink or large waterproof container, line the container of your choice (with drain holes) with a large piece of cheesecloth, making sure there is enough cheesecloth to cover the top of the mixture. Carefully pour the hot mixture into the container. Cover with the cheesecloth and a lid or small plate. Place a weight of about 1 ½ pounds on top (we used cans and a bag of flour) or the lid or plate. Let sit for about 15 minutes.
- Carefully unwrap tofu. You can eat it immediately, or store it in the refrigerator in a container of water for 1 to 2 weeks, changing the water daily.